This disclosure relates to systems and methods for separating hydrophobic fluids (such as oils) which are entrained as aerosols, from gas streams (for example, air streams). Preferred arrangements also provide for filtration of other fine contaminants, for example carbon material, from the gas streams. Methods for conducting the separations are also provided.
Certain gas streams, such as blow-by gases from diesel engines, carry substantial amounts of entrained oils therein, as aerosol. The majority of the oil droplets within the aerosol are generally within the size of 0.1-5.0 microns.
In addition, such gas streams also carry substantial amounts of fine contaminant, such as carbon contaminants. Such contaminants generally have an average particle size of about 0.5-3.0 microns.
In some systems, it is desirable to vent such gases to the atmosphere. In general, it is preferred that before the gases are vented to the atmosphere, they be cleaned of a substantial portion of the aerosol and/or organic particulate contaminants therein.
In other instances, it is desirable to direct the air or gas stream into equipment. When such is the case, it may be desirable to separate aerosol and/or particulates from the stream during the circulation, in order to provide such benefits as: reduced negative effects on the downstream equipment; improved efficiency; recapture of otherwise lost oils; and/or to address environmental concerns.
A variety of efforts have been directed to the above types of concerns. The variables toward which improvements are desired generally concern the following: (a) size/efficiency concerns; that is, a desire for good efficiency of separation while at the same time avoidance of a requirement for a large separator system; (b) cost/efficiency; that is, a desire for good or high efficiency without the requirement of substantially expensive systems; (c) versatility; that is, development of systems that can be adapted for a wide variety of applications and uses, without significant re-engineering; and, (d) cleanability/regeneratability; that is, development of systems which can be readily cleaned (or regenerated) if such becomes desired, after prolonged use.
A filter arrangement is provided that includes a first stage coalescer filter and a second stage filter element downstream from the coalescer filter. Preferably, the first stage coalescer filter comprises a non-woven fibrous media. The second stage filter element will preferably include pleated media. Preferred constructions will include a filter element including a tubular extension of pleated media defining an open filter interior; a first end cap at one end of the tubular extension of pleated media; the first end cap having an aperture in communication with the open filter interior; a second end cap at an end of the tubular extension of media opposite of the first end cap; the second end cap having an aperture in communication with the open filter interior; and a region of fibrous media oriented in the first end cap aperture; the region of fibrous media including first and second, opposite flow faces; the second flow face being oriented toward the open filter interior; and the first flow face being oriented away from the open filter interior.
The disclosure also describes a filter element comprising a tubular extension of media defining an open filter interior; a first end cap at one end of the tubular extension of media; the first end cap having an aperture in communication with the open filter interior; the first end cap having an outer, annular surface; the outer, annular surface comprising a polymeric material positioned to form a radial seal with a housing, when the filter element is operably mounted in a housing; and a second end cap at an end of the tubular extension of media opposite of the first end cap; the second end cap having an aperture in communication with the open filter interior, the second end cap having an outer, annular surface; the second end cap outer, annular surface comprising a polymeric material positioned to form a radial seal with a housing, when the filter element is operably mounted in a housing.
The disclosure also describes an end cap arrangement comprising a ring of compressible, polymeric material; the ring having a center aperture centered in the ring and an outer, annular surface; the center aperture having a first greatest dimension across the aperture, and the ring having a second greatest dimension across the ring; the first greatest dimension being not greater than 50% of the second greatest dimension; the outer, annular surface comprising polyurethane foam having an as molded density of about 14-22 pounds per cubic foot; a frame construction oriented in the center and potted within the ring; and a region of fibrous media held by the frame construction.
The disclosure also describes a filter arrangement comprising a housing construction defining an interior and having a gas flow inlet, a gas flow outlet, and a liquid flow outlet; a filter element operably positioned in the housing construction; the filter element including: a tubular extension of media defining an open filter interior; a first end cap at one end of the tubular extension of media; the first end cap having an aperture in communication with the open filter interior; a region of fibrous media oriented in the first end cap aperture; the region of fibrous media being constructed and arranged to separate at least a portion of a liquid phase from gases with an entrained liquid; a gas flow direction arrangement constructed and arranged to direct gas flow from the gas flow inlet, through the region of fibrous media, into the open filter interior, through the tubular extension of media, and out through the gas flow outlet; and a liquid collection arrangement constructed and arranged to direct liquid collected by the region of fibrous media to the liquid flow outlet.
There is also described a diesel engine blow-by recovery system comprising: a diesel engine having a size of at least 50 HP and a crankcase; a filter arrangement in gas flow communication with the crankcase; the filter arrangement including: a housing having a gas flow inlet arrangement, a gas flow outlet arrangement, and a liquid flow outlet arrangement; a filter element operably positioned in the housing and including: a tubular extension of media defining an open filter interior; a first end cap at one end of the tubular extension of media; the first end cap having an aperture in communication with the open filter interior; a region of fibrous media oriented in the first end cap aperture; a gas flow direction arrangement constructed and arranged to direct gas flow from the gas flow inlet arrangement, through the region of fibrous media, into the open filter interior, through the tubular extension of media, and out through the gas flow outlet arrangement; and a liquid collection arrangement constructed and arranged to direct liquid collected by the region of fibrous media to the liquid flow outlet arrangement.
In another aspect, the disclosure describes a method of treating diesel engine blow-by gases; the method comprising steps of: directing blow-by gases from a diesel engine to an coalescer filter; the coalescer filter being mounted in an interior of a tubular pleated media filter; removing at least a portion of a liquid phase from the gases with the coalescer filter as a collected liquid; after the step of removing at least a portion of a liquid phase, directing the gases through the tubular pleated media filter; filtering at least a portion of particulates from the gases with the pleated media filter; and after the step of removing at least a portion of the collected liquid phase, directing drainage of at least a portion of the collected liquid from the coalescer filter, along the interior of the tubular pleated media filter, to a drain construction.